6" x 20" or 20" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 22.5"] 12in diameter these grilles offer both functionality LO246 Product Details Size 32 Compatible with Duct 4"

these grilles offer both functionality and aesthetic appeal

+ Product Details Size - 25"w X 20"h is the size for the duct opening measurement only

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If your duct opening is 14 inches in diameter

6" x 20" or 20" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum White [Outer Dimensions: 8.5" X 22.5"] 12in diameter these grilles offer both functionality LO246 Product Details Size 32 Compatible with Duct 4" these grilles offer both functionality and aesthetic appeal + Product Details Size 25"w X 20"h is the size for the duct opening measurement only